The U-235 released!

Here's a new DIY project that I have been working on for a while -
the U-235 Suboctave Generator.

In short, it's an analog monophonic octave down pedal.

I wanted to do something a bit different, so this pedal uses a CD4046 PLL to do the freqeuency dividing, insted of a D-flip flop that are typically used in analog octave down pedals. This allowed me to add a couple of fun features like the Detuned Mode and the CV input.

Here's a short demo (the fun part starts at about 2 minutes in...)

It will work best for guitar since the tracking gets alittle bit slower at the lower notes, but you can clean up the tracking by using the neck pickup. I also have found that it helps alot to palm-mute the strings alittle bit when playing the lowest notes.

I will not share the schematic for the U-235, so please don't ask for it. But when I have time I will try to write another part for the CMOS Workshop series that will explain how to set up the 4046 as a frequency divider so that you can breadboard it yourself and play around with it.

I hope you like it. :)

PCB avaliable now in the shop
Assembled pedals coming soon

U-235 Suboctave Generator PCB

In the last half of the demo I'm using the "New Wave CV Generator" (more info on that project coming soon) as a Control Voltage source, but you can hook up any LFO, from a synthesizer or another pedal.

..or why not build your own simple square wave LFO on a piece of veroboard and put it in the same enclosure? :)

Building tip: Make the input and output wires as short as possible. There's alot of high amplitude square waves going on inside the circuit and it can easily bleed into the clean signalpath, making it sound less clean than it's supposed to be. Never run the wires under/over the board. Just a small thing to keep in mind.